1. Field of the Invention
This specification relates to a switchboard with a position-indicating apparatus, and more particularly, a switchboard with a position-indicating apparatus, capable of externally indicating a position of a truck, which moves with a circuit breaker or a transformer mounted thereon, without an error.
2. Background of the Invention
In general, a circuit breaker refers to an electric protection device which protects a load device and a wire from a fault current upon an occurrence of a fault, such as short-circuit, earth fault and the like, on an electric circuit.
Such circuit breakers are classified into an oil circuit breaker using oil as an arc-extinguishing medium, a gas circuit breaker using sulfar hexafluoride (SF6) which is an inert gas, an air circuit breaker using air as an arc-extinguishing medium, a circuit breaker using magnetism, a vacuum circuit breaker using dielectric strength of vacuum, and the like.
In recent time, most of electric appliances use sulfar hexafluoride (SF6), which exhibits superior arc-extinguishment and insulating performance, as an insulating medium. However, the sulfar hexafluoride (SF6) causes the greenhouse effect, which is 23,900 times of carbon dioxide, and thus its use is restricted worldwide.
Active developments of eco-friendly electric apparatuses using media which can replace the sulfar hexafluoride (SF6) are undergoing. Demand for a vacuum circuit breaker which is one of such eco-friendly electric apparatuses is rapidly increasing.
The vacuum circuit breaker generally serves to control power transfer and protect a power system, and has an increasing application range from an intermediate voltage to a high voltage, from the perspective of its great breaking capacity, high reliability and stability, and a need of a small installation space.
The vacuum circuit breaker is installed along with a switchboard, in which several electric apparatuses including a circuit breaker are accommodated and managed for an operation or control of a power station, a substation and the like, an operation of a motor, etc., and is used by being accommodated in a cradle fixed to the switchboard.
In the switchboard having such vacuum circuit breaker, a metering transformer chamber is formed at a lower portion of a cradle, and a transformer is installed in the transformer chamber. The transformer as well as the circuit breaker is mounted on a truck. The truck with the transformer and the circuit breaker moves to a test position for maintenance and an operation position (or a driving position) where it is connected to a load terminal to perform transformation.
FIG. 1 is a schematic view of a switchboard according to the related art.
As illustrated in FIG. 1, a switchboard 10 with a vacuum circuit breaker includes a vacuum circuit breaker chamber 11 accommodating a vacuum circuit breaker 12 therein, a transformer chamber 13 located below the vacuum circuit breaker chamber 11 and accommodating a transformer 14 therein. The transformer chamber 13 can be open using a transformer door 17.
The vacuum circuit breaker 12 is provided in the vacuum circuit breaker chamber 11. The transformer 14 which is mounted on a truck 16 moves in the transformer chamber 13 to the test position or the operation position. A power fuse 18 is provided at a top of the transformer 14, and a ground switch 15 is provided at a rear surface of the switchboard 10.
The related art switchboard having such configuration is not provided with a separate apparatus for preventing a position of the vacuum circuit breaker 12 or the transformer 14 from being wrongly (erroneously) indicated to the exterior, upon externally indicating the position of the vacuum circuit breaker 12 or the transformer 14. This makes it difficult to check an accurate position of the vacuum circuit breaker 12 or the transformer 14 from the exterior.
Also, because of non-employment of an apparatus for preventing the position of the vacuum circuit breaker 12 or the transformer 14 from being indicated as a different (or wrong) position to the exterior, an operator misunderstands the operation position as the test position when the vacuum circuit breaker 12 or the transformer 13 is located at the operation position, and accordingly opens a vacuum circuit breaker door or the transformer door 17. This results in frequent occurrence of accidents, such as an electric shock and the like.